Ryan O'Neal's Heartbreak over Critically Ill Farrah

In an exclusive interview with PEOPLE, an emotional and often teary-eyed Ryan O’Neal spoke for the first time about the devastating illness of his longtime partner, Farrah Fawcett, who has battled cancer for the past two and a half years.

“It’s a love story. I just don’t know how to play this one. I won’t know this world without her,” O’Neal, 68, says of his current role as caretaker. “Cancer is an insidious enemy.”

Revealing for the first time how the anal cancer long ago spread to other parts of Fawcett’s body, including her liver, O’Neal says, “She stays in bed now. The doctors see that she is comfortable. Farrah is on IVs, but some of that is for nourishment. The treatment has pretty much ended.”

Fawcett, 62, herself tells of her journey through illness in Farrah’s Story a two-hour NBC documentary the onetime Charlie’s Angels icon shot with pal Alana Stewart that airs Friday, May 15.

The Fateful Day

“It was never meant to be a documentary,” says Stewart, 63. “Farrah just took her little hand-held camera to the doctor one day.” It was the day, as it turned out, that Fawcett learned from her doctors the cancer she thought she had licked had returned.

“Farrah was devastated,” says O’Neal. “It was horrible, terrible news.” Despite this, Fawcett chose to keep the camera running. Says Stewart: “She wanted to tell the truth. There were times I’d stop filming because I thought it was too personal and she said, ‘This is what people go through with cancer. Film it.’ So I would.”

Farrah’s Story details Fawcett’s trips overseas for medical treatment not readily available in the U.S. “They really didn’t know what to do in the States,” says O’Neal. All in all over a period of two years, the ailing actress visited Germany six times and was under the supervising care of Dr. Ursula Jacob of the Alpenpark Clinic. “We had great promise,” continues O’Neal. “There were times when there seemed to be positive results. Farrah was even playing tennis.”

Sadly, Fawcett’s condition worsened. “At about the halfway point in our trips the news started to get darker and darker and darker,” says O’Neal. “The hope started to fade. But not for Farrah. She continued fighting. There was always a courage there, and a quiet dignity. Farrah never changed. I fell in love with her all over again because of how she handled this.”

Her Days Now

Fawcett now spends her days at home, often asleep. “She stays in bed,” says O’Neal. “It’s a nice bed.” She receives visits from a few close friends – including fellow Charlie’s Angels stars Jaclyn Smith and Kate Jackson and, when able, likes to watch TV, especially Dominick Dunne’s cable program Power, Privilege and Justice.

Another visitor has been Fawcett and O’Neal’s son Redmond, who, behind bars for a drug-related probation violation, on April 25 was allowed three hours at home with his mother to say what might be his final goodbye. In his jail-issued jumpsuit and in shackles, Redmond is seen in the NBC documentary climbing into his sleeping mother’s bed and crying. “Oh my gosh, my gosh,” he says as he hugs the frail figure next to him. “Oh, my gosh.”

“Farrah doesn’t know Redmond’s in trouble,” says O’Neal. “And Redmond is terrified for his mother. ‘I don’t want to be in jail and have some guard tell me she is gone,’ he said to me. I told him, ‘She’s rebounding.’ I lied to him. I lie to her. It’s the best thing.” Redmond, meanwhile, is awaiting transfer to a lockdown rehab facility.

No Vanity

A particularly cruel aspect of the disease is that Fawcett has now lost her iconic golden tresses. “The hair is gone,” says O’Neal. “Her famous hair. I have it at home. She didn’t care. I rub her head. It’s kind of fun, actually, this great, tiny little head. How she carried all that hair I’ll never know. She doesn’t have a vanity about it.”

For now, O’Neal struggles to keep hope alive and to avoid facing the future without the love of his life. “I can’t hear a song, I can’t pass places that we were together, without being stabbed in the heart,” he says. “A week ago Farrah said to me, ‘Am I going to make it?’ I said, ‘Yes, you’ll make it. And if you don’t, I’ll go with you.’

“Farrah has never, ever talked about how unfair it is,” concludes O’Neal. “But I’ve thought about it. She may have thought to herself that she had been chosen to do this, that some higher power had put her in this situation. Because then there would be something positive to come out of it. And maybe that’s true. But I’m just not so sure it’s something positive for Farrah.”

For the complete story of Farrah Fawcett and her current condition, pick up the new issue of PEOPLE, on newsstands Friday